finally happens before return in a try #493issue-493-2

In a try block such as:

  if expr:
    try:
      return
    finally
      print
  pass

the print happens before the return and cannot be followed by
pass. The general case is that when the body/else/handlers in a try
block all have return, break etc., the code behind finally: has no arc
to the statement following the try block.

close #493

2 files changed, 25 insertions, 5 deletions

diff --git a/coverage/parser.py b/coverage/parser.py
index 71334b6..3d46bfa 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -842,19 +842,21 @@ class AstArcAnalyzer(object):
                 try_block.return_from           # or a `return`.
             )
 
-            exits = self.add_body_arcs(node.finalbody, prev_starts=final_from)
+            final_exits = self.add_body_arcs(node.finalbody, prev_starts=final_from)
             if try_block.break_from:
-                break_exits = self._combine_finally_starts(try_block.break_from, exits)
+                break_exits = self._combine_finally_starts(try_block.break_from, final_exits)
                 self.process_break_exits(break_exits)
             if try_block.continue_from:
-                continue_exits = self._combine_finally_starts(try_block.continue_from, exits)
+                continue_exits = self._combine_finally_starts(try_block.continue_from, final_exits)
                 self.process_continue_exits(continue_exits)
             if try_block.raise_from:
-                raise_exits = self._combine_finally_starts(try_block.raise_from, exits)
+                raise_exits = self._combine_finally_starts(try_block.raise_from, final_exits)
                 self.process_raise_exits(raise_exits)
             if try_block.return_from:
-                return_exits = self._combine_finally_starts(try_block.return_from, exits)
+                return_exits = self._combine_finally_starts(try_block.return_from, final_exits)
                 self.process_return_exits(return_exits)
+            if exits:
+                exits = final_exits
 
         return exits
 
diff --git a/tests/test_arcs.py b/tests/test_arcs.py
index b03ac53..a245e21 100644
--- a/tests/test_arcs.py
+++ b/tests/test_arcs.py
@@ -774,6 +774,24 @@ class ExceptionArcTest(CoverageTest):
             arcz=".1 12 28 89 9.  -23 34 46 6-2",
         )
 
+    def test_return_finally_before_return(self):
+        self.check_coverage("""\
+            a = []
+            def check_token(data):
+                if data:
+                    try:
+                        return 1
+                    finally:
+                        a.append(1)
+                return 2
+            assert 2 == check_token(False)
+            assert [] == a
+            assert 1 == check_token(True)
+            assert [1] == a
+            """,
+            arcz=".1 12 29 9A AB BC C-1 -23 34 45 57 7-2 38 8-2",
+        )
+
     def test_except_jump_finally(self):
         self.check_coverage("""\
             def func(x):